Schematics for the Cuban Islander Double Sideband Transceiver (Please Send More Info)

 

Jose CO6EC has been digging up 30 year-old Islander schematics for us.  Thanks Jose.  This one shows a VFO for the Islander.   Note that it runs on 80 meters, but they select the second harmonic at 40 meters.  This was a smart move that surely helped with VFO frequency stability. 

Jose sent this printed circuit board pattern for the VFO.  Obviously they were making many of these rigs. 

Here is the power supply.  Jose reports that the transformer came out of a Soviet Krim 218 TV set.  As a kid, I also pulled a transformer out of an old TV -- I did it to build a power supply for a Heath HW-32A. 

Here is another version of the Islander.  Click on the image for  a better view.  Jose reports that this version was circulating during the time Islanders were being built.  He says this diagram many have been done by Arnie Coro CO2KK (SK), and may have been circulated on the internet. 

Here's the first schematic that Jose sent.  Again, click on the image for a better view. 

I will continue to gather information on the Islander and the Jaguey.  If you have any info please send it to me.  

Here are some earlier posts on these rigs: 

https://soldersmoke.blogspot.com/2023/03/the-islander-homebrew-dsb-rig-from-cuba.html

https://soldersmoke.blogspot.com/2023/03/needed-more-info-on-cuban-islander-or.html

Thanks to Jose CO6EC!  

Troubleshooting an Intermittent with Mr. Carlson. And Troublesome Tube Re-Branding.

This is a really great video on how Mr. Carlson (VE7ZWZ) did troubleshooting on a tube-type receiver. The problem was an intermittent.  They can drive you nuts, but Mr. Carlson show us how to stay sane. 

-- His use of ordinary observation at the start of the process is very important.  He notices a flickering glow in the voltage regulator tube.  The flickering coincides with the intermittent noise that he is trying to fix.  That is an important clue. 

-- He also can see that the grid of one of the AF amplifier tubes is getting way too hot: grid emission.  That is another important clue.  

-- He checks the grid voltage on the AF amplifier and finds that it is way too low.  It is fine on the other side of the resistor that carries the voltage to the tube.  But it is close to zero at the grid.   This means that the mica capacitors on the grid are suspect. 

-- He uses some fairly esoteric test gear -- a homemade device and an an old Heathkit signal tester -- to check his diagnosis.  They confirm that the mica caps are the problem.  He replaces the caps and the problem is gone.  A very satisfying troubleshoot. 

Mr. Carlson presents us with a lot of good info: 

-- 6K6 tubes were often in fact 6V6 tubes.  And 12AX7s were often 6VJ8s!  Manufacturers were deliberately re-branding tubes. So we shouldn't be surprised if some of our solid state devices turn out to be a bit different from what was promised.  This practice goes way back. 

-- I liked Mr. Carlson's final sensitivity test on the receiver -- he just waved his hand near the antenna connection and we could hear the receiver respond.  Excellent. 

-- Mr. Carlson is very negative about the use of polystyrene caps in oscillator circuits.  But we these simple and cheap caps being used to good effect in oscillators in India.  

-- The leaky and bad micas were a bit surprising.  Carlson speculates that their proximity to heat-producing resistors might have caused the trouble. 

Finally, it is interesting to hear the Canadian pronunciation of radio words:  Solder with the L pronounced (as in the UK).  Farad with the second A long and the final D emphasized (I say it just as the first two syllables of Michael Faraday's last name). 

Thanks Mr. Carlson. 

Mr. Carlson Replaces Old Capacitors -- Bathtub Capacitors

I recently posted a video from CuriousMarc about whether or not to replace electrolytic capacitors in old pieces of gear.  This is a hot topic in restoration circles. 

This week Mr. Carlson put out a video (above) in which he got rid of a bunch of "bathtub" capacitors in an old receiver. 

One of the many interesting things in Mr. Carlson's video was how his test gear initially showed the old capacitors to be good, but on further examination with better test gear he found them to be BAD! 

Out with old, in with the new!  

To Re-Cap or Not to Re-Cap -- Curious Marc on the Electrolytic Controversy in Ham Radio

A while back I got some fairly acerbic feedback when I DARED to suggest that perhaps it would be a good idea to replace the old electrolytic capacitors in ham radio equipment.  It was as if I had attacked motherhood and apple pie!   

Yesterday I was looking at CuriousMarc's YouTube channel and I came across the above video.  While I had been in the preemptive replacement camp, Marc makes a good case for leaving some of the old caps in place.   The fact that the electrolytics usually are open when they fail, and that there are fuses in the power supply to protect the transformers,  are important points.  His admonition not to replace electrolytics with tantalum caps (which fail closed) was also very useful. 

OK, my flame-proof suit is on! 

CuriousMarc (AJ6JV) Goes to a Hamfest

Jean Shepherd once said that all of us at one point come to a cross-roads in our lives -- one road leads to success, the other to ham radio flea markets.  

As I watched this, I realized that CuriousMarc sounds like a ham.   Sure enough, some Googling revealed that his real name is Jean-Marc Verdiell and his ham radio callsign is AJ6JV. 

I knew Marc was one of us when, in the video, he opens up the teletype.  He says that the seller claimed that it still worked.  But Marc comments that he hopes that this is not true, so that they will be able to troubleshoot and fix the device.  FB.  That's the spirit.  

We are really lucky to have someone as successful and creative as Marc in the ranks of ham radio operators.  

Be careful with the high voltage Marc!  

Hammarlund HQ-100 Misidentified in 1963 FCC Film

Oh the indignity!  It appears at 7 minutes 16 seconds in this FCC film.  It is clearly an HQ-100, but the FCC subtitles identify it at an HQ-110.  It is clearly an HQ-100 ( the model without the clock). 

https://www.youtube.com/watch?v=LzPIOfpKkRM

As the owner and operator of what must be one of the few remaining HQ-100s, I feel obligated to defend the reputation of this fine piece of shortwave gear.   

How many of you have HQ-100s?  

R-390s, KWM-2s, Airplanes, and Magnetic Loops -- A Really Interesting Interview with Ted Robinson K1QAR

Eric Guth 4Z1UG has a really interesting interview with Ted Robinson K1QAR.  

I really enjoyed hearing Ted's inspiring story: 

https://www.youtube.com/watch?v=SUUzlKMMANg

https://www.qsotoday.com/podcasts/K1QAR

Listeners will like the discussion of the R-390 and the KWM-2.  And his talk about airplanes.  And the joy of repair.  

Here is Ted's QRZ.com page:  https://www.qrz.com/db/K1QAR

Thanks Eric!  Thanks Ted! 

Mr. Carlson's New Lab and Workbench

I am very glad to see that Mr. Carlson is NOT slowing down.  In fact he has built another lab and is ramping up.  FB!  

Solid-Stating an HT-37 VFO -- Advice Needed

 

Original HT-37 VFO Circuit

A couple of things before I start:  

First, this is not my fault.  The Radio Gods are to blame.  I innocently tried to by an HT-37 tuning capacitor on e-bay, but the seller sent me the entire VFO unit.  The only thing missing was THE TUBE. Clearly, that was a sign, right?  

Second, this is a work in progress.  That is why my diagram (below) is a bit ugly.  I am looking for your input and advice on how I might do this better.  I will understand if religious principles prevent some of you from participating in this endeavor. 

I am trying to solid-state this device WITHOUT major surgery, and without adding any reactive components that would change the resonance or tuning range of the original.  The original circuit tunes from 5 to 5.5 MHz and that is fine with me.  

I started out by just sticking a J-310 FET into pins 1, 2, and 5 of the tube socket.  I put 12 V on the drain and the thing oscillated right where it is supposed to.  That was a good sign.  

Here is what I have done so far: 

Bill's initial solid state conversion of HT-37 VFO

Mechanically, my effort has been very simple.  At first I tried to fashion a more serious male socket for the FET using two broken 7 pin tubes.  This didn't work well.   

So then I just ran three short wires up through the center hold of the tube socket to the connections for pins 1,2, and 5.   I superglued the J-301 to the chassis and made some non-reactive connections: I put a 47 ohm resistor on the source,  and a 220 ohm resistor on the drain. I grounded the drain for RF with a .01 uF cap to ground.    I added a 100k resistor and a diode on the gate.   Oh yea, I put a couple of ferrite bead on the FET gate lead.  (See pictures below.)

Three lead up through the center hole

A rare look inside an HT-37 VFO

The original thermatron circuit has an output bandpass transformer, a 3900 ohm resistor and a coupling cap.  I left them in the circuit, but they are not doing anything. 

The output from the source of the FET looks pretty good.  I can see some VHF on the trace, but I suspect this is from my FM broadcast nemesis at 100.3 FM (one mile away).  On a receiver, I can hear some AF noise on the signal, but this may be the result of the RFI from THE BIG 100 -- WASHINGTON'S CLASSIC ROCK. 

So what do you folks think?  What else could I do, or should I do?  

TRIGGER WARNING: Solid-Stating Old Tube (Thermatron) Gear (Including -- GASP -- R-390As)

Look at that.  Well, maybe some of you shouldn't. (I'm thinking of you Grayson.)  I found the Charles Smith YouTube channel while innocently looking for ideas on how to solid-state the HT-37 VFO assembly I recently bought on e-bay.  Charles Smith has some really great ideas in this area.  He solid-stated a Heath VF-1.  But he took it all to an extreme when he solid stated an R-390A.   Take a look at how he built the replacements for the thermatrons:  He used those plastic wall sockets that you screw into sheet-rock when you need to hang a picture.  This is real genius. He used the tube filament lines to carry DC to these new sockets. 

R390A Solid State Conversion Video #1:  https://www.youtube.com/watch?v=xhWzX874wYo

Charles Smith's YouTube Channel 

https://www.youtube.com/channel/UCpfh8gxL64qd22RaNPR-QFw/videos

He has videos on the HQ-170 (DEAN:  Just say NO!) and the SP-600.  He also covers the HQ-110, which is uncomfortably close to my HQ-100.  

Who is Charles Smith?   What is his callsign?    Charles Smith is KV4JT.  Here is his QRZ page: 

https://www.qrz.com/db/KV4JT

He has some great humor and wisdom in his videos: Procedures that are difficult or more trouble than they are worth are called "bugger-bears."  He advises that if your IF cans are stuck, you should "find a way to unstick them!"  Indeed you should!  He builds a cool jig to hold the IF section of the R-390A while you are working on it.  He provides similar protection (with two long screws) to the VF-1.  

Even though some of you will have to go to therapy after seeing all this, I say THREE CHEERS FOR CHARLES SMITH! 

SolderSmoke Podcast #239: Hex DX, VFO Temp Comp, DC RX, Polyakov!, DX-100, Wireless Set, Farhan's "Daylight Again" HDR rig, MAILBAG

N2CQR Hex Beam Aimed at Europe

SolderSmoke #239 is available for download: 

http://soldersmoke.com/soldersmoke239.mp3

TRAVELOGUE: 

James Webb Space Telescope.  Mars returning to opposition in early December.   

BILL'S BENCH

Hex Beam K4KIO - on roof – TV Rotor – 20-17-12  Lots of fun.  Working Japan regularly, Australia, South Africa on long path 17,000 miles.  52 countries SSB since July 11.

VFOs and Temp stabilization.  Dean KK4DAS found my ceramic resonator VFO for DC receiver drifty. He was right.  So I built a real LC Colpitts VFO.  Got me into temp stabilization.  A new hobby!  An obsession.  HT-37 and Ht-32 parts. Ovens?  WU2D’s second VFO video.  Understanding thermal drift and how to address it. Split stator caps.  Cut and try.  

Built a Polyakov DC Receiver. https://soldersmoke.blogspot.com/2010/03/polyakov-plus-dual-band-receiver-with.html  Lauser Plus.  Lauser = Imp or Young Rascal!  DK2RS.  He used a ceramic Resonator VXO at 3.58 MHz.   Mine works great on 40 with VFO running 3.5 -- 3.65 MHz. See schematic below. 

On 40 AM with DX-100 and MMMRX.  DX-100 died.  12BY7 VFO buffer went bad.  How common is failure in this tube type?  Nice QSO with Tim WA1HLR about the DX-100.

Got my Dominican license:  HI7/N2CQR!  SSSS on the way.   Thanks to Radio Club Dominicano and INDOTEL.

Getting more active in the Vienna Wireless Society.  

BOOK REVIEW:  

"The History of the Universe in 21 Stars” by Giles Sparrow.  Written during the pandemic.  Published by Welbeck, in London. https://www.amazon.com/History-Universe-21-Stars-imposters/dp/1787394654  Also:  From “Atoms to Amperes” by F.A. Wilson available for download.  See blog.

SHAMELESS COMMERCE DIVISION:   

Todd K7TFC getting ready to launch “Mostly DIY RF.”   I used his TIA boards in my 1712 rig.  He will have boards like this and much more.  Stay tuned.

I need more viewers on YouTube.  They want 4,000 hours IN A CALENDAR YEAR!  Please watch!

FARHAN’S NEW “DAYLIGHT AGAIN” RIG.  Analog.  VFO.   Comments, observations. We need to get him on the podcast.  Maybe two shows: SDR and HDR. 

PETE'S BENCH

Time very limited. But still sharing lots of tribal wisdom.

Wireless set with tubes!

Tool recommendation – Air compressor

 MAILBAG:

Farhan VU2ESE – Speaking of big antennas “Whenever I look at the huge construction cranes in Hyderabad, I always think how one could make 160m, 4 element yagi using it as a boom..”

Todd K7TFC in Spain, spotting Log Periodics in Madrid.

Andreas DL1AJG:  Can Biologists fix Radios?

Janis AB2RA Wireless Girl.  Expert on Hammarlunds.  And was my first contact with the Tuna Tin 2. She too was HB!

Peter Parker VK3YE on Owen Duffy VK1OD

Lex PH2LB on homebrew radio

Would this really be homebrew?  Mail from H-A-D article on FM receiver

F4IET a DSB rig from France

Ciprian got his ticket YO6DXE    

Josh G3MOT sent us a good video about the Vanguard satellite and IGY.

Dave Wilcox K8WPE bought Chuck Penson’s Heathkit book.

Rogier -- So many great articles and links from PA1ZZ

Bill AH6FC  Aloha. Retiring.  Wants to build.  Mahalo!

Grayson KJ7UM  Working on an Si5351.  Gasp.

Mike KE0TPE viewing YouTube while monitoring 6 meters.   He will have a lot of time to watch!

Chris KD4PBJ spotted Don KM4UDX from VWS FB

Mark WB8YMV building a superhet.  Having trouble with 455 kc IF can filter.

Walter KA4KXX Great comment on the Daylight Again rig. 

Ramakrishnan Now VU2JXN was VU3RDD.  Found lost Kindle with SolderSmoke book on it. Building SDR rig from junk box.  Trouble with the LM386. 

Pete, Farhan and Tony:  Shelves of Shame

Daylight Again by Farhan

The Polyakov receiver I built yesterday (from SPRAT 110, 2002!)

A Surprisingly Good Movie from the Late 1960s: "The Ham's Wide World" (Video)

I found this movie to be surprisingly good.  Narrated by Arthur Godfrey, it features Barry Goldwater, and a lot of other hams.  There is a homebrewer too!  Lots of  old rigs we know and love:  a Drake 2-B, a couple of Galaxy Vs, a Benton Harbor lunchbox, Heathkit SB-series rigs, many Swans, and was that an HQ-170 that I saw in there?  There are also many cool antennas, including a 15 meter quad set up by a bunch of Southern California teenagers. 

Near the end, when they visit ARRL Headquarters, we briefly see none-other-than Doug DeMaw, W1FB!  FB!  

Please take a look at this video and post comments about the rigs, antennas, and radio amateurs that you see in the film. 

Details on Pete N6QW's Wireless Set

Details on this wonderful project:  https://www.n6qw.com/Wireless.html

Pete's blog post: http://n6qw.blogspot.com/2022/06/what-is-wireless-set.html

SolderSmoke blog link to video:

https://soldersmoke.blogspot.com/2022/06/pete-n6qws-hybrid-wireless-set-think-of.html

Pete N6QW's Hybrid Wireless Set -- A Thing of Beauty, with Thermatrons

Pete Juliano is amazing.  He is admirably carrying a very heavy load of family responsibilities.  But  he still can build some really unique and innovative rigs.  He tells us that getting up at 3 am and only sleeping 5 hours per night allows him to do this.

Pete also blames Grayson Evans KJ7UM for this rig, what with the thrematrons and all.  Pete has a 7360 mixer in this rig, something that Grayson had in the 3rd edition of his Hollow-State Design book (get yours here:  https://www.ermag.com/product/hollow-state-design-2nd-edition/).  Pete reports that he first built the chassis for the tube (I mean thermatron) portion of the rig in the 1970s -- it has been in his junkbox ever since.  Grayson admires Pete's compact construction and point-to-point wiring.  

I too noticed very poor conditions on Field Day this year.  

Three cheers for Pete Juliano!  

W8ZAP on 40 AM with a Collins 20V3 Broadcast Transmitter

 

I was on 40 AM yesterday morning and I talked to Jerry W8ZAP (great callsign) out in Michigan.  Jerry was running his Collins 20V3 (above on the right), which was originally an AM broadcast band transmitter.  FB.  

Here is Jerry's QRZ.com page: https://www.qrz.com/db/W8ZAP

More info on the 20V3: https://collinsaerospacemuseum.org/products/product_sheets/20V-3%20AM%20Transmitter%20Product%20Sheet.pdf 

Hammarlund and Homebrew Heroine: Janis AB2RA, HQ-100 Filter Cap Question

 

I was searching for Hammarlund HQ-100 wisdom when Google pointed me to the Electric Radio articles of Janis AB2RA.  They were in  ER #380 and #381 (February and March 2021).  Lots of good stuff  in there.  

This morning I happened upon a 2014 SolderSmoke blog post (as you do) about my Tuna Tin 2. Turns out that Janis was my first contact with this rig.  And she too was running a homebrew rig. TRGHS. 

https://soldersmoke.blogspot.com/2014/03/i-too-built-tuna-tin-2.html

I continue to work on my HQ-100.  The AC hum is getting worse so I have ordered a replacement capacitor can from Hayseed Hamfest.   But I was a bit confused about which cap to order.  Hayseed has two caps listed for the HQ-100 -- one (it seems) for the early model of this receiver and one for later models.  Is that right?  Did Hammarlund update the power supply to add filter capacitors?  Take a look: 

https://hayseedhamfest.com/collections/hammarlund

Dean KK4DAS is getting ready to work on his dad's HQ-170A.  He too will find lots of wisdom and tribal knowledge on Janis's wonderful web site.  

Her main page: http://www.wireless-girl.com/  (with a vast amount of technical info available through the links on the upper left side of this page) 

About Janis: http://www.wireless-girl.com/AboutMe.html

Thanks Janis!  

The Original Wireless Girl

http://www.wireless-girl.com/OrigWirelessGirl.html

A Great Book on Oscillators (Analog LC Oscillators) by John F. Rider (Free!)

 

Thanks to Peter Parker VK3YE for alerting us to this wonderful 1940 book.  John F. Rider -- a real hero of electronic literature -- does a great job in discussing the practical aspects of oscillator circuits. 

This excerpt from Rider's foreword gives a sense of the approach taken in this book: 

The book covers a lot of material.  In addition to the standard oscillator circuits, he discussed multivibrators, relaxation oscillators and much more.  There is a chapter on magnetostriction in which he shows that this property is the basis for crystal oscillators AND the mechanical filters that we are familiar with.  In fact he seems to take what we would consider a mechanical filter and put it in the grid circuit of a tube to make an oscillator. 

He discussed the modulation of oscillators. He describes the Heising modulator that caused young Jean Shepherd so much teenage heartache.  

Download the book here: 

https://worldradiohistory.com/BOOKSHELF-ARH/Rider-Books/Rider-The-Oscillator-At-Work-Rider-1940.pdf?fbclid=IwAR3MfTnhXtrxbUFRMYB1nFu1S2lBugdlAHrqnIO6IGnCMntLggGrvCIroFE

SolderSmoke FDIM Interviews: A BRAVE HAM! Grayson Evans KJ7UM Presents a 50 Watt Amplifier to THE QRP GROUP!

Wow, talk about walking into the lions' den!  Grayson Evans, author of "Hollow State Design" and guru of all things thermatronic, went to FDIM and made a presentation TO THE QRP GROUP on how to build a 50 watt amplifier with a 6146 thermatron.  In New York that would have been called chutzpah.  The QRP ARCI guys seem to have tolerated this QRO-heresy; I'm not so sure the zealots over in G-QRP would have been quite so tolerant.

Grayson gave a nice shout out to SolderSmoke's Pete Juliano.  

And he offered some sage advice to those who live in fear of high voltage:  "Don't touch anything with high voltage on it."  Words to live by my friends.  He even managed to call those who shy away from high voltage "wimps."    This was all very reminiscent of the unforgettable safety advice he offered in his August 2021 interview on Ham Radio Workbench: "Try not to swallow anything, and don't sit on the thermatrons." I mean, who can argue with that? 

You can listen to Bob Crane's interview with Grayson here (about 6 minutes total): 

http://soldersmoke.com/2022 KJ7UM.mp3

Check out Grayson's  Hollow-State Design Book 3rd Edition: tinyurl.com/hollowstatedesign3

Check out Grayson's technical blog:kj7um.wordpress.com

Thanks Bob and thanks Grayson. 

Frank Jones's Homebrew Rig -- as described by Michael Hopkins AB5L (SK)

"Frank is all homebrew. His receiver is unshielded outside, but built around a central square of aluminum that houses a Velvet Vernier dial thru the front panel and some tubes I did not recognize jutting horizontally on both sides of the box where coils also plug in. The transmitter is a multi-stage affair on a piece of particle board. The tubes are vertical here, and the bench was littered with brown Hammarlund coils labeled 5, 10, 20, and 80."   

https://soldersmoke.blogspot.com/2021/07/summer-reading-for-homebrewers-frank.html

https://qsl.net/ve7sl/jones%20oscillator.html

W1VD's Boatanchor Receiver Tests

I've been trying to get more rigorous in my evaluation of receiver performance.   My HQ-100 is tuned to Radio Marti, and it sounds great.  But how great is it really?  And what about all the receivers and transceivers I have built?  How good are they?  

Our friend Dean KK4DAS is about to start the rehabilitation of his dad's old HQ-170A.   A search for that receiver led me to Jay Rusgrove's very interesting measurement and analysis of old tube type radios.  Jay's results appear in the links below.  More important is his very clear description of how the tests were done and what the results mean (link below). Also included is one link showing a discussion of Jay's work.  

Jay notes: 

The decision of which boat anchor receiver(s) to own is seldom based on performance alone. A combination of favored manufacturer, period of manufacture, features, collectability or even just 'looks' often rank higher on the priority list than receiver performance. Even if one were interested in performance specs much of the available information is subjective as few receivers manufactured prior to the mid 70s have undergone standardized testing. Hard data on minimum discernable signal (MDS), blocking and two-tone IMD dynamic range is interesting to some operators and important in an historical context as it shows the progression of receiver development.

Jay designed the very first real transmitter that I homebrewed (The VXO 6 Watter from QRP Classics). Jay has been mentioned many times in the SolderSmoke podcast and blog:    

Jay's results:   http://www.w1vd.com/BAreceivertest.html

Jay's methods:  http://www.w1vd.com/Receivermeasurementbasics.html

Discussion: https://www.antiqueradios.com/forums/viewtopic.php?t=96872